s Identification of tRNA-Derived Fragments Expression Profile in Breast Cancer Tissues

Background: In recent years, tRFs(transfer RNA-Derived Fragments) and transfer RNADerived Stress-induced RNAs (or tRNA halves) have been shown to have vital roles in cancer biology. We aimed to reveal the expression profile of tRNA-derived fragments in breast cancer tissues in the study, and to explore their potential as biomarkers of breast cancer. Methods: We characterized the tRNA-derived fragments expression profile from 6 paired clinical breast cancer tissues and adjacent normal samples. Then we selected 6 significantly expressed tRNAderived fragments and screened the genes for validation by using Quantitative Real-time PCR. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes biological pathway were finally analyzed. Results: We found 30 differentially expressed tRNA-derived fragments across our dataset, out of which 17 were up-regulated, and 13 were down-regulated. Compared with 16 clinical breast cancer tissues and adjacent normal tissues by qPCR, the results demonstrated that tRF-32-Q99P9P9NH57SJ (FC = -2.6476, p = 0.0189), tRF-17-79MP9PP (FC = -4.8984, p = 0.0276) and tRF-32- XSXMSL73VL4YK (FC = 6.5781, p = 0.0226) were significantly expressed in breast cancer tissues (p < 0.001). tRF-32-XSXMSL73VL4YK was significantly up-regulated, and tRF-32- Q99P9P9NH57SJ and tRF-17-79MP9PP were significantly down-regulated in which the expression patterns were similar to the sequencing results. The top ten significant results of GO and KEGG pathways enrichment analysis were presented. Conclusion: Our studies have demonstrated that there were significantly expressed tRNA-derived fragments in breast cancer tissues. They are hopefully to become biomarkers and would be valuable researches in this area.